Chronic lung disease (CLD) or bronchopulmonary dysplasia (BPD) is a disease of premature babies who required prolonged support with their breathing and supplemental oxygen. These babies are at high risk of many short and long-term problems with their breathing, growth and development, including death in infancy or childhood. Studies have shown that these babies have higher energy expenditure and lower energy intake compared with babies without CLD/BPD. Increasing energy intake for these babies beyond standard levels may therefore seem beneficial. However, setting high targets for energy intake for these babies may not be achievable. Furthermore, methods of increasing energy intake such as increasing the milk volume or concentration or giving intravenous nutrition may lead to complications of their own. We planned to examine whether increasing energy intake for these babies improves their breathing status, their growth and development, and reduces their risk of death without producing significant complications. Having found no suitable study to date that answers these questions, we are currently unable to provide any evidence on whether increasing the energy intake for babies with (or developing) CLD/BPD is overall beneficial.

Authors' conclusions:

To date, no randomised controlled trials are available that examine the effects of increased versus standard energy intake for preterm infants with (or developing) CLD/BPD. Research should be directed at evaluating the effects of various levels of energy intake on this group of infants on clinically important outcomes like mortality, respiratory status, growth and neurodevelopment. The benefits and harms of various ways of increasing energy intake, including higher energy density of milk feed and/or fluid volume (clinically realistic target volume should be set), parenteral nutrition, and the use of various constituents of energy like carbohydrate, protein and fat for this purpose also need to be assessed.

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Background:

Preterm infants with bronchopulmonary dysplasia (BPD)/chronic lung disease (CLD) have nutritional deficits that may contribute to short and long term morbidity and mortality. Increasing the daily energy intake for these infants may improve their respiratory, growth and neurodevelopmental outcomes.

Objectives:

To assess the effect of increased energy intake on mortality and respiratory, growth and neurodevelopmental outcomes for preterm infants with (or developing) CLD/BPD. Secondarily, the review examines any adverse effects associated with increased energy intake.

Search strategy:

The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of the Cochrane Central Register of Controlled Trials, MEDLINE (accessed via Ovid), references cited in previous relevant Cochrane reviews and in other relevant studies, review articles, standard textbooks, and manuals of neonatal medicine. Hand search results of the Cochrane Neonatal Review Group were also assessed. Search was updated in December 2010.

Selection criteria:

All randomised and quasi-randomised trials comparing the outcomes of preterm infants with (or developing) CLD/BPD who had either increased (> 135 kcal/kg/day) or standard energy intake (98 to 135 kcal/kg/day). Increasing energy intake might be achieved enterally and/or parenterally; enterally by increasing the energy content of the milk, increasing feed volume, or by nutrient supplementation with protein, carbohydrate or fat. The primary outcomes were the development of CLD and neonatal mortality; secondary outcomes included respiratory morbidities, growth, neurodevelopmental status and possible complications with increased energy intake.

Data collection and analysis:

We planned to extract data using the standard methods of the Cochrane Neonatal Review Group. Relevant trials would be scrutinized for methodological quality independently by the review authors to determine their eligibility for inclusion. Data of the included trials would be expressed as relative risk, risk difference, NNT and weighted mean difference where appropriate, using a fixed effect model.

Main results:

No eligible trials were identified. Fourteen studies that appeared to be relevant were excluded, as no study directly compared increased versus standard energy intakes in infants with CLD/BPD. However, two excluded trials provided some insights into the topic. One study showed that infants with CLD/BPD who were fed formula enriched with protein and minerals had improved growth parameters up until the cessation of the intervention at three months of corrected age. The other study compared different energy density of formula but identical energy intake by setting different feed volumes for both groups. It showed that both groups were unable to achieve the pre-designated feed volumes and that there were no differences in growth, respiratory outcomes, oedema and the diuretic requirements.